Halogenated carboxylic acids



United States Patent Ofifice 3,311,566 Patented Mar. 28, 196'? 3,311,566 HALOGENATED CARBOXYLIC ACIDS Murray Hauptschein, Glenside, and Maurice Miville,

Flourtown, Pa., assignors to Pennsalt Chemicals Corporation, Philadelphia, Pa, a corporation of Pennsyl- Vania No Drawing. Filed Oct. 13, 1965, Ser. No. 495,720

9 Claims. (Cl. 252-356) This invention relates to synergistic mixtures of highly fluorinated monocarboxylic acids and water soluble deriv-atives thereof.

This application is a continuation-in-part of application S.N. 283,612 filed May v27, 1963, of Murray Hauptschein et al. for Halogenated Carboxylic Acids, which application has been abandoned.

It is known that highly fluorinated monocarboxylic acids and water soluble derivatives thereof, particularly the perfluorinated acids and derivatives, display remarkably high surfactant activity, due undoubtedly to the extremely low surface energy of the fluorinated portion of the molecule.

It has been found that the surfactant activity of such materials, in terms of the minimum concentration necessary to provide a desired reduction of interfacial tensions in a given system, is largely dependent upon the length of the fluoroalkyl chain. By this standard, the lower perfluorinated acids, viz: trifluoroacetic to perfluorohexanoic acid, having relatively low surfactant activity, while the higher acids such as perfluorooctanoic acid and above have increasingly higher surfactant activity, i.e. smaller and smaller amounts are required to produce a desired reduction of interfacial tensions.

Since the highly fluorinated, and particularly the perfluorinated acids and derivatives, are relatively very expensive materials, it is of the utmost importance that they be effective in small concentrations, and for this reason the shorter chain acids, such as perfiuorobutyric or perfiuorohexanoic, which are effective only in relatively large concentrations, are not used. Considering only the surfactant activity it would appear desirable to use long chain acids such as perfi'uorodecanoic, perfluoroundecanoic or perfluorododecanoic in preference to acids of intermediate chain length such as perfluorooctanoic or perfluorononanoic. However, although the surfactant activity continues to improve as the chain length increases, beyond seven or eight carbon atoms in the fluoroalkyl chain, the rate of improvement tapers off while the cost of the longer chain acid goes up rapidly. Furthermore,

other difliculties arise, such as lack of Water solubility, which tend to limit the use of the long chain acids as surfactants. At the present time, due to these limitations, only acids of intermediate length, in particular perfluorooctanoic acid, are used commercially as high performance surfactants such as in the emulsion polymerization of fluorinated olefins such as tetrafluoroethylene, chlorotrifluoroethylene and the like.

In accordance with the present invention it has now been found that certain mixtures of perfluorinated or monochloroperfluorinated monocarboxyric acids or water soluble derivatives thereof containing a major proportion of intermediate chain length compounds, viz compounds containing a .fiuoroalkyl chain of from .five to eight carbon atoms in length, and a minor proportion of higher chain length compounds, viz compounds containing a chain of from nine to twelve carbon atoms in length display surfactant activity which is far greater than that dis. played by a compound having a chain length equivalent to the average for the mixture.

The synergistic mixtures of the invention are comprised of perfluoro or monochloroperfiuorocarboxylic acids or derivatives thereof, of sufficient water solubility for surfactant activity, which compounds have the general formula ZCJnii-OX Where Z is selected from the'class consisting of fluorine and chlorine; where n is an integer from six to thirteen; Where the fluoroalkyl group ZC F has a chain length of from five to twelve carbon atoms, and where X is hydrogen or a cation. The mixtures of the invention contain from 55% to 90% by weight of at least one compound of the above formula having a fluoroalkyl chain length of from five to seven carbon atoms and where n is not more than 8, and not more than 45% nor less than 10% by weight of at least one compound of the above formula having a fluoroalkyl chain length of from nine to twelve carbon atoms and where n is not more than 13. By the term fluoroalkyl chain length is meant the longest straight fluoroalkyl carbon chain in the compound ignoring branching. Preferably the mixtures contain from 60% to of at least one compound of the above formula having a fluoroalkyl chain length of from five to seven carbon atoms and from 20% to 40% of at least one compound having a fluoroalkyl chain length of from nine to twelve carbon atoms. Best results are obtained when the mixture comprises at least three compounds with at least two of the compounds having a fluoroalkyl chain of from five to seven carbon atoms in length and having not more than 8 carbons in the fluoroalkyl group and,

making up over 55% by weight of the mixture; such as a mixture having e.g. 30% by weight of a compound having a fluoroalkyl chain of 5 carbon atoms in length, 35% of a compound having a fluoroalkyl chain of 7 carbon atoms in length and 35% of a compound or compounds having a fluoroalkyl chain of from 9 to 11 carbon atoms in length.

Particularly preferred are mixtures of the above type wherein the compounds are the free acids or the alkali metal, ammonium, or'alkyl substituted ammonium salts thereof; in other words, where X is selected from the class consisting of hydrogen, alkali metal (particularly sodium and potassium), ammonium or alkyl substituted ammonium, such as methylammonium, ethylammonium, dimethylammonium, diethylammonium, trimethylammonium, etc.

The mixtures of the above acids or water soluble derivatives thereof may be prepared in a number of ways. A preferred method is to start with perfluorinated or monochloroperfluorinated iodides of the proper chain length. These fiuorinated iodide precursors may be prepared by telomerization procedures such as by the reaction of 2-io-doperfluoropropane, CF CFICF or 2-iodoperfluoroethane CFgCFzI, with tetrafluoroethylene to produce telomers of the formula (CF CF[CF CF ],,I and CF CF [CF CF ],,I respectively; or by the reaction of l-chloro 2 iodo hexafluoropropane, CF CFICF CI or 1-chloro-2-iodotetrafiuoroethane CF ClCF I with tetrafluoroethylene to produce telomers of the formula.

CFzClOFKtFzCFzkI and CF ClCF [CF CF I respectively. Suitable procedures for preparing the precursor telomer iodides are described for examples in U.S. Patent 3,156,732 of Murray Hauptschein et al.

From the standpoint of cost savings the mixtures of acids derived from the series of telomer iodides s)2 2 2)n and l CF2C1CF(CF2GF2)nI are particularly preferred.

The precursor perfluorinated or monochloroperfluorinated iodides may be converted to the acid by reaction of the iodide with chlorosulfonic or fluosulfonic acid following the procedure described in detail in co-pending application Ser. No. 310,500, filed Sept. 20, 1963 of Murray Hauptschein and Milton Braid for Halogenated Organic Compounds. The perfluorin-ated or monochloroperfluorinated chlorosulfates or fluosulfates thus obtained may be readily hydrolyzed to the acid.

The precusor perfluorinated or monochloroperfluorinated iodides may likewise be converted to the acids by the reaction of the iodides with fuming sulfuric acid as described in co-pending application Ser. No. 212,137 filed July 24, 1962 of Murray Hauptschein et al. Such a reaction produces a mixture of acid and acid fluoride. The acid fluoride may be readily hydrolyzed to the acid by known procedures.

When perfluorinated or monochloroperfluorinated iodides are used as precursors for the preparation of the acids, the desired mixtures of acids or derivatives in the proper proportions may, if desired, be obtained by starting with a mixture of iodides which will give the desired mixture of acids in the final product. Since the -CF I group of the iodides is converted to the carboxyl group in the process, the starting iodide should, of course, have one more carbon atom in the fluoroalkyl portion than is desired in the fluoroalkyl portion of the final product.

On the other hand, instead of starting with mixtures of iodides to give the desired mixtures of acids directly, individual iodides may be converted to the individual acids and then the mixtures prepared synthetically by mixing the acids or derivatives in the desired proportions.

The examples which follow illustrate both the direct preparation of the mixtures by starting with mixtures of iodides and the preparation of individual compounds which are then later mixed in the desired proportions to produce the synergistic mixtures of the invention.

It is understood, of course, that other methods for preparing the fluorinated acids and derivatives making up the mixtures of the invention may be employed. For example, the lower members having up to about eight carbon atoms in the entire molecule may be prepared if desired by the electrochemical fluorination of the corresponding hydrocarbon carboxylic acid in liquid hydrogen fluoride as described for example in United States Patent 2,519,983 of Simons.

The following examples illustrate the preparation of acid mixtures and individual acids which may be then combined in proper proportions to form the synergistic mixtures of the invention starting with perfluorinated or monochloroperfluorinated iodides or the corresponding chlorosulfates derived therefrom.

EXAMPLE 1.PREPARATION OF MIXED SUR- FACTANTS CFs CF2C1CF(CF2)11COOH This example illustrates the preparation of a mixture of acids and corresponding salts of the series CFzClCFKJFzMCOOH from the corresponding chlorosulfates. A mixture of chlorosulfates consisting of about 28% by weight of R CF2ClCF(CF2CF2)2OSO2Cl 36% by weight of I CF2ClCF(CF2CF2)aOSOzCl 24% by weight of I CFzOlCF(OFgCF2)4OSOrOl and 12% by weight of is prepared from a mixture of the corresponding iodides consisting of i CF2ClCF(GFzOF2)2I B.P. 70 C. at 20 mm. Hg,

t CF2ClCF(CFzCFz)3I B.P. 99 C. at 20 mm. Hg,

OFs

CFgClCF(CFzCFz)4I B.P. 128 C. at 20 mm. Hg, and

OF2OIOF(CF2OF2)5I B.P. 130 C. at 5 mm. Hg. This mixture of telomer iodides (627 grams) and 1165 grams of chlorosulfonic acid is added to a 2 liter, 3-necked flask equipped with a sealed bearing anchor-type stirrer, thermometer, heated 10 inch Vigreux column connected by means of a diameter heated glass tube to a receiver for collecting the iodine monochlorideiodine trichloride by-products produced. The reaction mixture is heated at -147 C. for 6 /2 hours while stirring. The flask is then cooled to room temperature and the chlorosulfate layer separated from the acid layer by simple phase separation. A total of 523 grams of chlorosulfates of the aforementioned composition is obtained.

A 200 gram portion of the above mixed telomer chlorosulfates is added gradually to 100 grams of sodium hydroxide in 1000 ml. of Water at a temperature of 75 C. over a period of 15 minutes while stirring. Disappearance of the lower chlorosulf-ate layer indicates completion of the reaction. The solution is allowed to cool to room temperature and acidified with 200 milliliters of 50% sulfuric acid, whereupon the organic acid separates out. The entire mixture is extracted with 500 milliliters of diethyl ether and the ethereal layer is washed with water and dried over anhydrous calcium sulfate. A portion of this ethereal solution is converted directly to the ammonium salt by treating with anhydrous ammonia gas and then evaporating the solvent, and finally drying under vacuum. The resulting white solid mixed acid gives the following analysis: Percent C, 21.67; percent H, 0.86; percent N, 2.60; percent F, 61.06; percent Cl, 7.20. This corresponds to the product C F a CF2C1CF(OF2)nCOONH4 where n has an average value of about 5. This mixture consists of 28% by weight of (ilFa CF2ClCF(OFa)5COONH4 36% by weight of CFzClCF(CFz)5COONH4 24% by weight of i CFzC1OF(CFz)1COONH4 and 12% by weight of CF2C1CF(CF2)9C0ONH4 and has an average chain length in the fluoroalkyl portion of 7.1. This mixture melts at to C.

Another portion of the ethereal solution is stripped of solvent and the residual acid distilled in vacuo to give themixed acids i GFzClCF(OF2)nCOOH of the above composition, boiling range of from 115 C.

at 28 mm. Hg to 147 C. at 2 mm. Hg. The acid mix ture is converted to the corresponding sodium, potassium and lithium salts by neutralization with NaOH, KOH and LiOH, respectively.

EXAMPLE 2.-PREPARATION OF (CF CF (CF COONH FROM (CF CF(CF OSO Cl To 87 grams of sodium hydroxide in 1000 milliliters of water is added 150 grams of (CF CF(CF OSO CL At a reaction temperature of 50 C. hydrolysis proceeds readily with hand stirring and the exotherrn of the reaction raises the temperature to about 65 C. A clear solution indicating complete hydrolysis is obtained in about minutes. The solution is cooled to room temperatureand acidified with 200 milliliters of 50% sulfuric acid, whereupon (CF CF(CF COOH separated out. The entire mixture is cooled to 5-l0 C. and washed with four 250 milliliters portions of ethyl ether. The ether solution is driedover anhydrous calcium sulfate, filtered, and ammonia gas bubbled into the solution to convert the acid into the ammonium salt. The ammonium salt, a white solid, was recovered by evaporation of the ether and subsequent drying at 4050 C. There is obtained 114.5 grams (92.8% yield) of the ammonium salt.

EXAMPLE 3.-PREPARATION OF (CF CF(CF CF OCO Cl A 226 gram sample of (CF CF(CF CF OSO C1 is saponified with sodium hydroxide solution by a procedure similar to that shown in Example 2. The reaction mixture is worked up as in Example 2 to yield 79% of the pure ammonium salt (CF CF(CF COONH EXAMPLE 4.-PREPARATION 'OF (CF CF (CF COONH FROM (CF CF (CF CF OSO Cl By procedures similar to those in Example 2 (CF3)2CF(CF2)7COONH4 is prepared in high yield.

EXAMPLE 5.--PREPARATION OF i CF201OF(CF2)7COOH from (JFa CF2C1CF(CF2)7OF2OSO2C1 The acid F OFQOIOF(OF2)7OOOH is prepared in 90% yield from the chlorosulfa (IJ s OFrOlOF(OF2)7OF2OSOzOl by the procedure described previously. An 81.4 gram sample of i OF2OlCF(OF2)-!COOH is dissolved in 250 milliliters of ethyl ether, and ammonia gas is passed int-o the solution until heat evolution ceases. Some precipitation occurred. The ether is then evaporated, and the last traces of solvent are removed from the solid product by heating to 65 C. in vacuo. There is obtained 83.8 grams (100% yield) of i O FrOlO (C 2)7GOONH4 EXAMPLE 6.PREPARATION OF PERFLUORO [9-METHYLDECANOIC] ACID FROM [CF 1 CF(CF I A 1 gallon stainless steel autoclave equipped with a turbine type agitator is charged with 1800 grams of fuming sulfuric acid (35 by weight of S0 and 600 grams of perfiuor-o[.9-methyldecyl]iodide B.P. 111 C. at 23 mm. Hg, M.P. 3637 C. The autoclave is sealed and heated with stirring at -175 C. for 2 hours, after which it is cooled to room temperature, opened, and the contents transferred to a separatory funnel while carefully excluding moisture from the product. The reaction mixture separates cleanly into a lower sulfuric acid phase and an upper organic phase. Upon careful separation of the two phases, 481 grams of organic material is collected and vacuum distilled. There is obtained 394 grams (84% yield) of the acid fluoride [CF3]2CF[CF2]7COF having a boiling point of 86 C. at 30 mm. Hg and 56 grams (11% yield) of the perfluo rinated acid [CF CF[CF COOH, M.P. 61-64 C. and a product hydrolyzable thereto, and about 20 grams (3%) of unreacted iodide. The infrared spectrum of the acid fluoride shows a characteristic strong peak at 5.30 while the carboxylic acid shows characteristic strong bands in the infrared spectrum at 3.20 1, 5.62p. and 6.95 The acid fluoride is saponified with a 10% sodium hydroxide solution, then acidified with sulfuric acid and extracted with ether. The dried ethereal layer is combined with the acid co-produced in the reaction and converted to the ammonium salt (CF CF(CF COONH by treatment with ammonia. The yields are essentially quantitative.

EXAMPLE 7.PREPARATION OF PERFLUORO 1 l-METHYLDODECANOIC] ACID FROM (CF CF(CF I A 1 gallon stainless steel autoclave equipped with a turbine-type agitator is charged with 562 grams of perfluoro[11-methyldodecyl1iodide, B.P. 137 C. at 18 mm. Hg and 1800 grams of fuming sulfuric acid (35% S0 The autoclave is sealed and heated with stirring at C. for 1.5 hours. The autoclave is cooled to 60 C. and the contents emptied by means of a dip pipe. On further cooling the organic product solidifies, permitting the spent sulfuric acid to be decanted off leaving 503 grams of organic product. The solid is dissolved in 700 grams of 1,1,2-trichlorotrifluoroethane and residual sulfuric acid removed by phase separation. After stripping ofl? the solvent, vacuum distillation of the organic product yields 326 grams (92% yield) of the acid fluoride [CF CF[CF COF having a boiling point of 88 C.

EXAMPLE 8.PREPARATION OF $1 3 0193 CF2C1CF CFD COOH FROM OF2ClCF(CF2)aI By a procedure similar to that of Example 6, 612 grams of v i cFioloFwFmr is allowed to react with 1800 grams of fuming sulfuric acid (35% by weight of S0 at a temperature of 135 for three hours. In addition to 15% of unreacted iodide, there is obtained an 88% yield of acid fluoride or, C-FzOlt3F(O-Fz)5COF and a 5% yield of carboxylic acid OF orrclt irr'ormooo'n and a product hydrolyzable thereto.

7 When the same reaction is carried out at 145 C. for three hours there is obtained 3% of unreacted iodide, an 87% yield of the acid fluoride and a 9% yield of carboxylic acid and a product hydrolyzable thereto. The

8 EXAMPLE IO.PREPARATION OF CF CI (CF COOH AND CF Cl (CF COOH AND THE CORRESPONDING AMMONIUM SALTS acid fluoride and acid are converted to the ammonium Ten grams 2 2( 2 2)3 P P in salt. ple 9 is allowed to react wit-h 33 grams of fuming sulfunc CF acid (35% by weight of S0 at 135 C. for 16 hours a in a Carius tube. From this reaction there is obtained OF2O1OF(OFZ)5COONH4 7.3 grams of crude product consisting mostly of the acid by the procedures described previously. fluoride CF Cl(CF COF having a boiling point of 74 Various physical constants and analytical data of the at 86 mm. Hg and acid CF Cl(CF COOH. The latter compounds prepared in this invention are summarized in was dissolved in ether and allowed to react with an excess Table I. of anhydrous ammonia to produce the ammonium salt,

CF CI (CF- COONH... EXAMPLE PREPARATION OF Analysis.-Calculated for 0 1 1 013 510 c, 21.43; H,

CF CICF (CF CF I AND CF CICF (CF CF I 0.89; N, 3.13. Found. C, 21.48, H, 0.65, N, 2.92.

2 2 2 2 4 Seven grams of CF Cl(CF CF I prepared in Example A 300 milliliter Monel autoclave is charged with 172 9 i llo ed t react with 24 grams of fuming sulfuric grams mole) f 1-chlOrO-Z-iodotetrafluoroethane, acid at 135-145 c. for 23 hours in a Carius tube. From 01 0101 1, and 83 grams (0.83 mole) of tetrafluorothis reaction there is obtained 5.2 grams of crude product ethylene. The autoclave is sealed and heated while shak consisting mostly of the acid fluoride CF Cl(CF COF, ing for 5 hours at 170 C. during which time the pressure having the characteristic band at 5.30 microns in the infradropped from 800 to 150 1bs./in. The autoclave is red spectrum, and the acid CF Cl(CF COOH, having allowed to cool and the reaction mixture is worked up. the characteristic bands at 3.30, 5.62, and 6.95 microns From this reaction there is recovered 9 grams of a mix- 25 in the infrared spectra. The acid is converted to the amture of unreacted tetrafluoroethylene and perfluorocyclom-onium salt CF Cl(CF COONH as described above. butane, 82.5 grams of unreacted CF ClCF I, 145.5 grams The very marked synergistic activity of the mixture of of telomer iodides of the formula CF ClCF (CF CF I the invention may be illustrated by the following series where the value of n ranges from one to about 10, and of tests in which the mixtures and individual compounds where the relative composition in percent by weight is: having a chain length equivalent to the average chain 25% of CF ClCF CF CF L B.P. 58 C. at 150 mm. Hg; length of the mixture are employed as surfactants in the 19% of CF ClCF (CF CF I, B.P. 68 C. at 48 m emulsion polymerization of vinylidene fluoride in aqueous Hg; 16% of CF ClCF (CF CF I, B.P. C. at 35 media. In the emulsion polymerization of fluorinated ole mm. Hg; 12% of CF ClCF (CF CF I, B.P. 111 C. at 35 fins such as Vinylidene fluoride, tetrafiuoroethylene and 20 mm. Hg; chlorotrifluoroethylene, the use of polyfluorinated surfac- TABLE I Analyses of Ammonium Salts Molecular Wt. Boiling Point of Physical Compound acid, C./- state of Calculated Found mm. Hg. acid Cald Neut. o H 01 F N o H 01 F N equiv CF3CFCF2COO0H /50 Liquid-.. 4.72 280.5 275 orrorwrmooorr 115/28 .-d5--- 21.15 1.01 8.92 57.4 3.52 21.28 0.42 8.92 57.7 3.52 380.5 382 (llFzCl OF3CF(CF2)5COOH 124/14 do 21.72 0.81 7.13 51.1 2.82 22.00 0.53 7.15 51.0 2.88 480.5 488 (EFZCI cn omonmooon *22.49 *0.21 7.38 *53.3 22.29 *0.85 *7.34 *59.5

CF3CF(CF2)1COOH 141/8 Solid 22.11 0.57 5.93 63.6 2.34 22.25 0.58 5.95 53.5 2.98 580.6 570 CF3CF(CF;)5COOH 11710.3 -.t1o-- 22.38 0.58 5.08 55.4 2.01 22.14 0.59 5.30 55.3 1.98 580.5 579 (CFa)2CFCFzCOOH 141/750 Liquid 21.35 1.48 60.8 4.98 21.39 2.59 59.7 5.58 254.1 254 (CF CF(OF OOOH 130/150 -do-.- 22.05 1.05 6 -8 8 .00 1.18 54.5 3.88

(CF3)2CF(CF2)5000H 115/20 Solid 22.47 0.84 57.1 2.91 22.42 0.84 57.9 3. 07 454.1 454 (CF3)2CF(OF2)7GOOH /10 do 22.73 0.59 58.7 2.41 22.72 0.71 58.5 2.51 554.1 555 (0Fr)2OF oFr)tC00H 117/0.5 155,111 22.92 0.59 59.7 2.05 22.85 0.55 59.3 6645 656 Analyses are for carboxylic acid in this instance. 10% of CF ClCF (CF CF I, 8% f tants has been found to be necessary in order to obtain CF ClCF (CF CF I 70 hlgh 1 Y, stable latices. In order to form a stable 2 2 2 2 5 latex, it is necessary that the polymerization mixture be 5% of CF ClCF (CF CF I; 3% of CF ClCF (CF CF I Wet by the aqueous polymerization medium. Otherwise, and 2% of CF ClCF (CF CF I where n is greater than F If at tends w 9agu1ate during lymerizanon producmg lumpy, non-umform polymer. In 8 and mostly 1n the range of 9 to 10. 75 view of the difiicultly wettable nature of these fluoropolymers, it is necessary to use a high performance surfactant which produces the maximum lowering of the surface tension of the system. The use of perfluorinated carboxylic acids particularly perfiuorooctanoic acid and its ammonium or alkali metal salts is well known for this purpose.

Because of the extreme high cost of these materials, it is of the utmost importance that they be efiective in the smallest possible concentrations. In accordance with the invention, it has been found that the mixtures of the perfiuorinated or monochloroperfiuorinated acids or derivatives of the invention of 'a given average chain length are effective in greatly decreased concentrations when compared against individual acids of equivalent chain length in the fluoroalkyl portion.

In each of the following tests, a 2 gallon horizontal polymerizer equipped with a paddle agitator was employed. Into the polymerizer there was charged 6300 grams of deionized water, containing the fluorosurfactant to be tested, together with 3 grams of a high melting, high purity, paraffin wax. The polymerizer was evacuated to remove air after which 9.0 grams of ditertiary butyl peroxide polymerization catalyst was injected. The agitator was turned on and the reactor heated to 245 F. at which point it was pressured to 650 lbs/in. gage with vinylidene fluoride monomer. Agitation, temperature and pressure was maintained until 900 grams of the monomer were absorbed over a period of 2%. to 3 hours. Monomer feed was turned oil and the temperature and agitation maintained for 1 additional hour after which the reactor was cooled and emptied, and the liquid containing suspended polymer was filtered through a 60 mesh screen. Any polymer solids remaining in the polymerizer were added to the solids on the screen filter. The non-latex solids (solids removed by the 60 mesh screen plus solids i remaining in the polymerizer) were then dried and weighed.

The performance of each run was rated on the basis of percentage of non-latex solids. Runs having less than 3% of non-latex solids were rated as excellent. Runs having from 3% to 5% non-latex solids were rated as good; runs having over 5% non-latex solids were rated as poor while those having over 10% non-latex solids were rated as very poor.

The results of 14 runs are shown in Table II. In Runs 1 and 2 individual surfactants were employed. In Run 1 the surfactant was 100% of the ammonium salt of I CF2CIOF[OF2]3COOH while in Run 2 the surfactant was the ammonium salt of In Runs 1 and 2, although 4 grams of surfactant were employed, the performance was very poor; mostly coagulated solids were obtained and very little latex indicating insufiicient surfactant activity. In Runs 3 and 4 the surfactant employed was the ammonium salt of the compound CF [CF COOH. In Run 3, at a usage of 4.0 grams of this surfactant an excellent latex was obtained. However, at a usage of 2.0 grams, poor results were obtained, i.e. more than 5% of non-latex solids.

Examination of Table II also reveals that in Runs '5 and 6 similar result were obtained when the ammonium salt of the individual surfactant of the formula was employed. At a usage of 4 grams, an excellent latex was obtained while at 2 grams more than 5% of non- 39 latex solids indicated unsatisfactory surfactant activity.

TABLE I SURFAC'IANT Performance Composition of Mirture, percent by wt. Run Amt, t Percent Type gms. ZCnFzn N0. of Carbons in ZC FZn Chain Nonlatex Rating Chain solids CFa 1 CFzC1( ]F[CF2] C OOH 4.0 5.0 100 Over 10 Very poor.

2 (CF3)2CF[CF2]11COOH '4. 5.0 100 do Do.

3 CFziCFzhC O OH 4. 0 7. 0 100 Less than 3 Excellent.

4 orao rare 0 on 2. 0 7. 0 100 Over a Poor.

Ch 7 CFZCIC JHCFABC OOH 4. 0 7. 0 100 Less than 3 Excellent.

CF; 7 '6 emulate Euro '0 011....-. 2. o 7. 0 100 Over 5 Poor.

7 CFzClCHCFflnC 0 OH 0.4 7. -l 28 36 24 12 Less than 3.... Excellent.

CF; 8 CFzCl( )F[CF2]nC O OH 0. 27 7. l 28 35 24 12 d0 D0.

CF; 9 OF2ClC F[OF2]nCOOI-I 0.4 7.1 30 35 20 15 ..(lo D0.

CFs orroldnoranooon 0.27 7.1 28 a2 24 16 do Do.

OFs 11 CFzC1C }F[CF2]nC 0 on... o. s' 1. 2 so 5 a ..do Do.

12 CF201CFlCF21nO 0 0H 0.4 7. 5 75 10 3 to 5 Good.

13 (CFs)2CF[CF2]nC O OH O. 27 7. 1 30 35 15 3 to 5 D0.

14 (CFghCFlCFahC O OH 0. 4 7. 1 2O 15 Less than 3- Excellent.

In sharp contrast to the relatively large amounts of surfactant required for the individual compounds in Runs 1 through 6 inclusive, mixtures of surfactants in accordance with the invention having an average chain length in the fluoroalkyl portion essentially the same as that in Runs 3 to 6 inclusive performed well at concentrations ranging from less than one-fourth to about one-fifteenth of that required for the individual surfactants of equivalent average chain length.

In addition to the cost savings resulting from the much lower concentrations required for the mixtures of the invention, the mixtures of the invention also have the advantage that they are inherently prepared more cheaply than the individual compounds when employing the telomer iodide precursors for their preparation in the manner previously described. The telomerization reaction tends to produce mixtures of compounds rather than individuals and more economical usage of the telonier product can be obtained by employing the product in ranges of molecular weight than as individual compounds. Thus, the mixtures of the invention are not only effective in lower concentrations but are likewise cheaper to prepare than individual compounds of corresponding average chain length.

The surfactant mixtures of the invention may be employed for any applications in which a high performance surfactant is required particularly where high chemical stability is also a desideratum. Thus, an addition to its use as a surfactant in the emulsion polymerization of olefins and particularly highly fluorinated olefins, the surfactant mixtures of the invention may also be employed as leveling agents for waxes, polishes and paints.

It will be understood as described in the preceding discussion that the synergistic mixtures of the invention are obtained directly by starting with appropriate mixtures of fluoroalkyl iodides or fluoroalkyl halosulfates which are then converted to the desired mixtures of acids or salts. Alternatively, the individual compounds (such as the individual alkali metal or ammonium salts) may be intimately mixed in the desired proportions by the usual mechanical methods such as a blender or mill to give the mixtures of the invention. The synergistic salt mixtures in accordance with this invention are stable, white, waxy, high melting solids (usually over 100 C.) which are water soluble and which are handled and used without difficulty or hazard. The ammonium salt mixtures also show solubility in other polar solvents such as alcohol and ether.

The mixtures of acids are usually viscous liquids, but sometimes these acid mixtures are low melting solids. The acid mixtures are also stable, non-hazardous materials and are handled without difficulty. They are soluble in ether and chlorofluorocarbons (e.g. trichlorotrifluoroethane) but have low solubility in benzene, hexane and heptane.

It is to be understood that numerous changes may be made from the above description and examples without departing from the spirit and scope of the invention.

We claim:

1. A mixture of fluorinated compounds having the general formula where Z is selected from the class consisting of fluorine and chlorine; where n is an integer from 6 to 13; where the fluoroalkyl group ZC F has a chain length of from 5 to 12 carbon atoms; and where X is selected from the class consisting of hydrogen, alkali metal, ammonium and lower alkyl substituted ammonium; said mixture containing from 55% to 90% by weight of at least one of said fluorinated compounds in which said fluoroalkyl group has a chain length of from 5 to 7 carbon atoms and not more than 8 carbon atoms in the fluoroalkyl group; and from 10% to 45% by weight of at least one of said fluorinated compounds in which the fluoroalkyl group has a chain length of from 9 to 12 carbon atoms.

2. A mixture in accordance with claim 1 in which Z is fluorine.

3. A mixture in accordance with claim 1 in which Z is chlorine.

A mixture of fluorinated compounds having the general formula where Z is selected from the class consisting of fluorine and chlorine; where n is an integer from 6 to 13; where the fluoroalkyl group ZC F has a chain length of from 5 to 12 carbon atoms; and where X is selected from the class consisting of hydrogen, alkali metal, ammonium and lower alkyl substituted ammonium; said mixture containing from 60% to by weight of at least one of said fluorinated compounds in which said fluoroalkyl group has a chain length of from 5 to 7 carbon atoms and not more than 8 carbon atoms in the fluoroalkyl group; and from 20 to 40% by weight of at least one of said fluorinated compounds in which said fluoroalkyl group has a chain length of from 9 to 12 carbon atoms.

5. A mixture in accordance with claim 4 in which Z is fluorine.

6. A mixture in accordance with claim 4 in which Z is chlorine.

7. A mixture of fluorinated compounds having the general formula II zonrrnoox where Z is selected from the class consisting of fluorine and chlorine; wherein n is an integer from 6 to 13 where the fluoroalkyl group ZC F has a chain length of from 5 to 12 carbon atoms; and where X is selected from the class consisting of hydrogen, alkali metal, ammonium and lower alkyl substituted ammonium; said mixture containing at least three compounds with at least two of the compounds having a fluoroalkyl chain of from 5 to 7 carbon atoms in length and having not more than 8 carbon atoms in the fluoroalkyl group and making up from 60% to 80% by weight of said mixture; the remaining portion of said mixture being made up of at least one of said fluorinated compounds having a fluoroalkyl chain of from 9 to 12 carbon atoms in length.

8. A mixture in accordance with claim 7 in which Z is fluorine.

9. A mixture in accordance with claim 7 in which Z is chlorine.

References Cited by the Examiner UNITED STATES PATENTS 2,806,866 9/1957 Barnart et a1. 260-408 LEON D. ROSDOL, Primary Examiner.

I. T. FEDIGAN, Assistant Examiner, 

1. A MIXTURE OF FLUORINATED COMPOUNDS HAVING THE GENERAL FORMULA 